The sustained release of active agents, e.g., exenatide, is known to be of value. In particular, long-term drug delivery has been shown to be effective in obtaining constant serum levels and in improving patient compliance.
Hydrogel membranes may be used for sustained delivery of active compounds. There are several theories regarding the mechanism of solute diffusion in hydrogels. The hydrogels that have been described have some porosity due to the network structure of the crosslinked polymer chains, which allow smaller molecules to diffuse through the structure. The size of the pores varies depending upon the hydrogel chemical composition and thus its degree of hydration. The hydrogels described in the art, however, are not particularly well adapted for delivery of large macromolecules, including bioactive proteins useful for the therapeutic treatment of humans and animals.
There is a need for delivery devices that provide controlled delivery of therapeutically effective amounts of bioactive polypeptides, which can be utilized in the treatment of a variety of diseases and pathological conditions in humans and animals.